The crystal structure of 2,2'-bipyridine

The crystal structure of 2,2'-bipyridine has been determined by single-crystal methods.The unit cell is monoclinic with a ----5.66,b = 6.24, c ----13.46 A, fl ~-118 ° 44'.The space group is P21/c-C~a, and there are two molecules per unit cell.Atomic positions were determined by electron-density projections and were refined by difference syntheses and by three-dimensional least-squares methods.Structure factors were obtained from visually estimated intensities on Weissenberg photographs taken with Cu Ka radiation.The molecule is planar and has a trans configuration.The C-:N bonds average 1.36 /~ and the C-C bonds in the pyridine ring average 1.39 A. The C-C bond between the two rings is 1-50 A. There are no short intermolecular distances, and binding must be due only to weak van der Waals forces.